Insulator for transformers



March 3, 1932. F. J. FISCHER INSULATOR FOR TRANSFORMERS Ei1ed July 2'7, .1929 6 Sheets-Sheet 1 March 1,1932. I F J. FISCHER 1,847,603 7 INSULATOR FOR TRANSFORMERS Filed July 2'7, 1929 GSheets-Sheet 2 Ma u'ch 1, 1932. J FISCHER 1,847,603

INSULATOR FOR TRANSFORMERS Filed July 27, 1929 6 SheetsSheet 4 Inventor: Franz J se M fi'scher y h g March 1, 1932. F. J, FISCHER INSULATOR FOR TRANSFORMERS Filed July 27, 192

6 Sheets-Sheet 5 I72 vezztor: Franz Jose 0h Fix/107' Patented Mar. 1, 1932 UNITED STATES ATENT; OFFICE FRANZ JOSEPH FISCHER, OF DRESDEN, GERMANY, ASSIGNOR TO THE FIRM KOCH 86 STEBZEL AKTIENGESEILSGHAFT, 0F DRESDEN, GERMANY INSULATOR FOR TRANSFORMERS Application filed July 27, 1929, Serial No. 381,651, and in Germany December 15, 1928.

iy invention relates to insulators for current or voltage transformers and it is a particular, though not exclusive, object ofmy invention to so design an insulator of this type that it is particularly useful in combination with measuring transformers.

To this end I so design the insulator that the unit constituted by the transformer and the insulator may be used independently or as a link in a chain of insulators.

It has already been proposed in a steppedup high-voltage transformer system to combine the several transformer units of a system into a chain, each unit comprising a pair of shells arranged with some clearance above each other and secured at the ends to parallel suspending members. The two shells of each unit are spaced by metal stays on which the transformer system is supported. As compared with this old arrangement, the unit according to my invention involves the advantage that the two lateral suspending members of the old arrangement are now replacedby a single member at the axis of the chain or unit so that space is saved, the system simplified. and its cost reduced. Any desired number of units ma 7 be combined into a chain, and any numher of chains may be connected with a high-voltage system in such manner that not the wires of the system are suspended but that conversely the chains or separate insulators, as the case may be, are suspended from the wires.

. In the drawings affixed to this specification and forming part thereof several devices embodying my invention are illustrated diagrammatically by way of example.

In the-drawings Figs. 1-4 illustrate diagrammatically various types of units,

Fig. 5 is an axial section of the unit illus trated in- Fig. 1, drawn to a larger scale,

Fig. 5a is apart section showing a modification,

Fig. 6 is a section on the line 6-6 in Fig. 5,

Fig. 7 is an axial section of a unit the insulator of which comprises a tunnel for sup porting thecoils of the transformer,

Fig. 7 a is a part section showing a modification,

Fig. 8 is a section'of a' tunnelled unit including a. current and a voltage transformer in a single insulator,

Fig. 8a is a part section showing a modification,

Figs. 9, 10, and 11 are diagrams of connections which may be applied to a chain of units according to my invention,

Fig. 12 is a partly sectional elevation showor other suitable material such as quartz sand, black lead or the like, 12 is a transformer which is indicated only diagrammatically in Figs. 1 to 4, but shown in detail in Figs. 5. and 6, and 13 isthe lid of the insulator which in the units illustrated in Figs. 1, 2,

5, and 6 is attachedto the top and in the units illustrated in Figs. 3 and 4 is attached to the base of the inverted insulator. The lid 13 is of conducting material in all cases.

The transformer 12, as shown in detail in a Fig. 5, is suspended from the lid by suitable brackets 16 and screws 13, and the lid is secured on the insulator 11 by an annulus 15, screws 15" and a packing washer 15". If desired, the lid 13 may be cemented to the insulator 11, as indicated at 14 in Fig. 5a. The transformer 12 comprises the usual iron core 43 which is held on the brackets 16 by means of an annular base plate 17 and screws 16'. As will appear from Fig. 6, the base plate is annular and should be carefully rounded at the edges. In this manner the transformer system is shielded from electri cal fields which is particularly desirable in a transformer having a rectangular and not' a circular iron core. 18 is the secondary, and 19 is the primary coil which as shown, are arranged co-axially.

With the transformer suspended from the lid 13 as illustrated the entire transformer is readily removed from the vessel 11 with the lid and as readily separated from the 11d by unscrewing the screws 13 so that the several parts of the units are readily assembled and taken apart for examination or exchange. Under certain conditions it may not be so particularly desirable to facilitate the assembling and exchanging operations, or several units may be combined so that it becomes necessary to insulate the iron core against the lid 13. In such cases ribs 20 as indicated in dotted lines in Fig. 5 may be provided at the base of the insulator for supporting and centering the base plate 17. I

The base of the insulator 11 may be provided with shielding ribs 26, particularly when the units are suspended in the open air. At its centre the base has a hollow boss 21., 23 is a pin, also hollow, which is inserted oiltightly in the bore of the hollow boss 21, 24 is a connecting terminal which is secured on the lower end of the hollow pin 23, and 25, 25 are the line wires which are connected with the primary coil by a conduit 22. 27 is a hollow suspending pin which is inserted oiltightly in the lid 13 and is connected with the line wires 25 through the conducting lid 13, the brackets 16, the iron shell core 43 of the transformer 12, the primary coil 19, the pin 23 and the terminal 24. The pin 27 is hollow for the reception of wires 28 and 29' which are connected with the secondary coil 18 and extended to wires 28 and 29 in a bowl 34 in the upper end of which the pin 27 is carried by means of a boss 35. The bearing faces of the boss and the bowl are spherical. 38 is a casing of sheet metal which is placed about the open sides of the bowl 34, 31 and 33 are insulated concentric metal cylinders in the upper end of the bowl 34 to which the wires 28 and 29 are secured by terminal brackets 37, 37 respectively, and 36 is the end of a unit arranged above the unit illustrated. The --bowl 34 is suspended from this unit by a hollow pin 33. In the case of a single unit, as illustrated in Figs. 1-4, the; bowl 34 is suspended from a grounded po e.

As shown in Figs. 14, the wires 28, 29 may be taken from the bowl 34 '(which has been omitted in this diagrammatic figure) to a voltmeter V, a relay, an ammeter, or any other instrument, not shown, or to the upper unit the lower end of which is indicated at 36 in Fig. 5. V

The hollow bowl 34 permits the ready arrangement of the terminals 37 which are protected by the sheet metal casing 38, and facilltates the assembling and disassembling of a plurality of superimposed units.

Fig. 2 illustrates a unit which is designed substantially as described with reference to Figs. 1 and 5 but in which the line wires 25 are arranged above the insulator 11 and the insulator is suspended from the wires by the pin 27 which in these diagrammatic illustrations is indicated bv a single line. The rimary coil 19 is grounded by a wire 39. he arrangements illustrated in Figs. 3 and 4 are similar in their general disposition to those illustrated in Figs. 1 and 2 but here the insulator 11 is suspended from the pin 27 and supports the lid. 13. The shields 26 in these two cases are arrangedpn the body of the insulator and not on its base, but otherwise the design is the same.

Referring now to Fig. 7 this illustrates a unit which is provided with an insulator 40 having a transverse passage or tunnel 42 as described in iny copending U. S. application 282,922. The primary coil 19 of the transformer is placed about the outer wall of the tunnel, the iron shell core 43 is within the tunnel, and the secondary coil 18 is seated on the core 43. By providing a bottle-shaped insulator consisting of a single part only the primary coil 19 is electrically protected throughout so that sparking-over within the insulator is avoided. The yokes of the shell core 43 extend about the insulator. 40 and are supported by a casing 46 of sheet metal which extends about the upper .end 45 of the insulator and in turn is suspended from a hollow pin 27. 48 is a screen which is supported on a. shoulder at the lower end of the shell 46 above the core 43. 26 are shields on the body of the insulator. 25, 25 are the line wires which are connected to the primary coil 19 and are suspended from the neck of the insulator, being connected to hollow ter minals 70 and 71 which are partly inserted in each other, and 72 is a bridging resistance intermediate the ends of the rimary coil 19. The wires 28 and 29 extend through the hollow pin 27 and are connected to an instrument of any kind, a relay or the like, as described with reference to Figs. 1-6. The insulator 14 may be filled with a mixture of quartz sand and black lead, or any other suitable material.

As illustrated in Fig. 7 a, the screen 48 may also be secured to a shoulder 46a on the casin 46 below the core 43 as shown in Fig. 7a.

eferring now to Fig. 8, this shows the combination of a current transformer C and a voltage transformer V. The insulator 59 is designed substantially on the lines illustrated in Fig. 7, that is, it comprises a substantially bottle-shaped body with a tunnel 42, a shell iron core 43, a primary coil 19 which is connected with the line wires 25, 25 and a secondary coil 18 on the core 43, as described with reference to Fig. 7. These parts constitute the current transformer C.

The voltage transformer V is arranged in the upper open part of the insulator 59 and is suspended from the lid 13 by brackets 16 as described with reference to Figs. 5 and 6. 56 is the iron core of the voltage transformer V, 60 is its primary coil which is connected wires 28 and 29 and the secondary 62 of the.

voltage transformer V is connected with wires 63 and 64 which are taken through the hollow pin 27 in the lid 13. Extending downwardly from a vertical flange on the lid 13 is a casing 65 which may be of conducting or insulating material and serves for protecting the wires 28 and 29 where they extend along the outer wall of the insulator 59, and also protects the yokes of the shell core 43 in the current transformer C.

The insulator 59 may be divided as shown in Fig. 8a. In-this case the insulator of the current transformer C is open at its upper end 57, and the insulator 58 of the voltage transformer is open at the bottom and contracted into a spigot 67 which is inserted in the upper open end 57 of the lower insulator 59. The two parts are joined by cementing or connected in any other suitable manner. Dividing the insulator facilitates the manufacture and reduces the cost but involves the up drawback that sparking-over may occur from the primary coil at the point where the upper and lower'insulatoi's are connected.

Referring now to Figs. 9, 10, and 11, these illustrate various systems of connections to which my insulator units may be adapted. The connections arenot described in detail as they are old in the art. Figs. 9 and 10 i1- lustrate three units 11 as described with reference to Fig. 1. The top unit is suspended from a pole or the like by the tube 33, Fig. 5, and the other units are suspended from this unit by a hollow pin 27,- as also shown in Fig. 5. Fig. 11 illustrates a similar arrangement with the bottle-shaped insulators 40 or 59 as shown in Figs. 7 and 8, in combination with an ammeter A. Current and voltage transformer systems may also be combined as indicated by the dotted lines 88. These lines represent conducting or capacitative voltage controls.

Referring now to Figs12, this illustrates a voltage transformer chain comprising three insulator units 11 of the type shown in Fig. 1 which are suspended from an eave at 78 by the tube 33 of the top unit. The eave 7 5 is part of a switch room S. The line wire 25 is spanned from the point 78 by a chain of insulators 74 connected with-the terminal 24 at the lowest-unit and taken to the room S by a wall-tube insulator 77 for a condenser, not shown. 76 are shields on the insulator.

By spanning the line wire 25 from the point 78 of the cave 75, I obtain the advantage that, as will appear from the diagram of forces, the resultant It extends substantially in the elongation of the cave 75 which is more favourable than the usual methods of suspension. Another advantage is that extra means for suspending the chain of trans formers are not required so that the chain may be adapted to any existing plant. I The parts of the line wire 25 which extend from the spanning terminal 7 3 to the terminal 24 at the end of the insulator chain, and from the terminal to the wall-tube condenser 77, are slack. 80 is an inspection passage for facilitating the access to the chain.

Instead of a voltage transformer chain as illustrated, a current transformer chain may be provided and in this case the line wires are taken to a terminal 70, 71 as illustrated in Figs. 7 and 8, and indicated in dotted lines in Fig. 12. A static voltage measuring instrument may be connected with the insulator 77 so that voltage and current are measured at this point. The chain may also be built up from combined voltage and current transformer units as shown in Fig. 8, or a current transformer chain may be combined with a voltage transformer chain, as indicated by the dotted lines 88 in Figs. 10 and 11. Referring now to Fig. 13, 81 is a pole from which the line wire 25 is spanned as described with reference to Fig. 12, and chains 11, 11 of voltage transformer units, and 40, 40 of current transformer units, respectively, are suspended from the pole and connected with the line wires 25 by terminals24 and 70, 71, respectively. 85 is a wire which is connected with the terminal 24 atone end and an oil switch, transformer or the like, which is indicated at 86, at the other end. It will appear that in this manner parts of the system within the plant are spanned from the chain 11, 11 of current transformer units. Instead of a transformer 86 or the like which. as shown, is moving on a track on the ground, the wire 85, or other branch wires, may be connected to a bus bar, not shown.

The described transformer units may be combined with any normal insulator chains in connection with any meansv or instruments which are employed for plants of this kind. My invention may further be adapted to choke coils and grounding choke-coils and the like. It does not make a difference whether the units, or chains of units, are used for power transforming or measuring purposes. The several systems may be connected in the insulators or chains as desired, and in general I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

In the claims affixed to this specification no selection of any particular modification of the invention is intended to the exclusion of other modifications thereof and the right to subsethan at the bottom and open at the bottom, a casing secured to the wider part of said insulator, a suspension pin on said casing and means adapted to be inserted in the open bottom end of said insulator for securing thereto a suspended part.

2. An insulator for transformers comprising an insulating casing, an iron core and a winding within said casing, means on said casing for suspending it from a part, means for suspending a part from said casing, and a lid on said casing for the reception of said first-mentioned suspended means.

3. An insulator for transformers c0mprising an insulating casing, an iron core and a winding within said-casing, means on said casing for suspending it from a part, ,means for suspending a part from said casing, both said suspending means including tubular parts for the reception of wires connected with said winding.

4. An insulator for transformers comprising an insulator casing, a laminated iron core within said casing, a plate for exerting pressure on said core, said plate being circular on the outside and rounded at its edges, a wind ing on said core, means on said casing for suspending it from a part, and means for suspending a part from said casing.

5. An insulator for transformers comprising an insulating casing, an iron core and a winding within said casing, means on said casing for suspending it from a part, means for suspending a part from said casing, and a lid on said casing for the reception of said first-mentioned suspending means, said lid and said casing being in direct contact. 6. An insulator for transformers comprising an insulating casing including a potshaped part, a voltage transformer in said pot-shaped part, a chamber connected with said pot-shaped part, a tunnel extending through said chamber, a current transformer in said chamber, means on said casing for suspending it from a part, and means forsuspending a part fromsaid casing.

7. An insulator for transformers comprising a bottle-shaped insulating casing with a tunnel therein, means on the wider part of said casing for suspending it from a part, and a bracket inserted in the narrow end or neck of-said casing for suspending a part from said casing.

8. An electric system comprising a line wire, an electric apparatus on the ground, and a system of insulators for measuring transformers intermediate said line wire and said apparatus, each insulator comprising an insulating casing, an iron core and a winding within said casing, means on said casing for suspending it from a part, and means for suspending a part from said casing, said winding in each insulator being so designed that the units of said system together constitute a stepped induction system.

9. An electric system comprising two systems of insulators, one of said systems constituting a current transformer and the other constituting a measuring transformer each system comprising a plurality of insulating casings, an iron core and a winding within each casing, means on said casings for connecting them with each other, means for suspending the topmost casing from a part, and means for suspending a part from the lowermost casing.

10. An insulator for measuring transformers comprising a pot-shaped insulating casing, a bottom forming part of said casing formed with an opening, a lid on said casing and suspended means in said opening and on said lid.

In testimony whereof I aflix m signature.

FRANZ JOSEPH F SCHER. 

